This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The twin-arginine translocation (Tat) system in bacteria ferries folded proteins across the cytoplasmic membrane. The core system is composed of three integral membrane proteins Tat A, B and C. This work is to solve the structure of TatC by X-ray crystallography.